The main aim of the European Organization for Research and Treatment of Cancer (EORTC) is to conduct, develop, coordinate and stimulate research in Europe on the experimental and clinical bases of cancer treatment in Europe. More than 2000 clinicians/researchers and 300 core medical institutions participate in the phase I, II and large, prospective, randomized, multi-center, phase III clinical trials carried out by 20 different E0RTC Cooperative Groups. The EORTC Data Center is a unique central facility in Europe that offers a comprehensive approach to cancer research and to the management of cancer clinical trials. The main objective of the EORTC Data Center is to provide logistic and scientific support to the EORTC Cooperative Groups with respect to the management of cancer clinical trials. This includes expertise in various areas such as protocol ans CRF development, regulatory requirements based on both national and international legislation, data management, computer, statistical and medical sciences as well as cancer related problems such as Quality of Life and Health Economics. It ensures from ain independent, objective, academic point of view, the highest possible quality of the trial, from its design to the final analysis and publication of the final results. The aim of this competing continuation grant application is to request continuation of the support that the EORTC Data Center has received without interruption since 1974 so that it can pursue, reinforce and expand the range of services which it offers to the well established network of investigators participating in the activities of the EORTC Cooperative Groups.